NASA's Gavin Schmidt said most of the record heat was from man-made climate change.
For third straight time, Earth sets hottest year record →
"This trend will continue; it will continue because we understand why it's happening," Gavin Schmidt, director of the NASA Goddard Institute of Space Studies, told the Associated Press. "It's happening because the dominant force is carbon dioxide."
Climate debate heats up after 2015 described as warmest year on record →